diff --git a/asc2log.c b/asc2log.c
index b14e7db..71be7f8 100644
--- a/asc2log.c
+++ b/asc2log.c
@@ -119,7 +119,7 @@ void calc_tv(struct timeval *tv, struct timeval *read_tv,
 		tv->tv_usec += read_tv->tv_usec;
 	}
 
-	if (tv->tv_usec > 1000000) {
+	if (tv->tv_usec >= 1000000) {
 		tv->tv_usec -= 1000000;
 		tv->tv_sec++;
 	}